ToME: the Tales of Maj'Eyal

Either free or steam/donator only? I'd love to have it remain in the game in some way as content shouldn't be cut entirely from all future releases for such silly reasons.

Don't think it'll assist as optional thing. There might be a replacing dungeon somewhere in the future or there might not.

There is an add-on to bring back breeding pits though.

Better to leave the Breeding Pits 'unofficial' at this juncture and distance the game from it then to invite trouble after having the discussion in regards to it.